The conventional engineer's seats employed on railway locomotives have tilting backs which are positioned manually and are retained in the selected position by a retractable pin type of locking device. My experience shows that these locking devices become unreliable under service conditions as a result, for example, of wear or damage. On occasion, sudden movement of the seat back resulting from unintended disengagement of the pin lock has resulted in personal injuries, and has given rise to law suits for damages.
The object of this invention is to provide an alternative to the tilt locks now being used which is relatively inexpensive and easy to manufacture and install, and yet is superior from both the safety and operational standpoints. According to the invention, the improved mechanism is a self-contained unit which, with but a simple change in the mounting bracket, is adaptable to most, if not all, of the engineer's seats now in service. The unit incorporates an adjusting screw which affords positive, infinitely variable control of the angle of tilt, is unaffected to any appreciable extent by wear, and, because it is an irreversible motion transmitter, inherently constitutes a reliable retainer for the seat back. In addition, the vital parts of the unit are protected, as far as practicable, by a housing, so malfunctions attributable to accidental damage or tampering are minimized. Finally, the new unit is suitable for use either as original equipment for new seats or as a replacement for the tilt lock employed on existing seats.